.\" Copyright (c) Andrey V. Elsukov <ae@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd November 7, 2014
.Dt ME 4
.Os
.Sh NAME
.Nm me
.Nd encapsulating network device
.Sh SYNOPSIS
To compile the
driver into the kernel, place the following line in the kernel
configuration file:
.Bd -ragged -offset indent
.Cd "device me"
.Ed
.Pp
Alternatively, to load the
driver as a module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_me_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
network interface pseudo device encapsulates datagrams
into IP.
These encapsulated datagrams are routed to a destination host,
where they are decapsulated and further routed to their final destination.
.Pp
.Nm
interfaces are dynamically created and destroyed with the
.Xr ifconfig 8
.Cm create
and
.Cm destroy
subcommands.
.Pp
This driver corresponds to RFC 2004.
Datagrams are encapsulated into IP with a shorter encapsulation.
The original
IP header is modified and the modifications are inserted between the
so modified header and the original payload.
The protocol number 55 is used for outer header.
.Sh NOTES
For correct operation, the
.Nm
device needs a route to the decapsulating host that does not run over the tunnel,
as this would be a loop.
.Sh SEE ALSO
.Xr gif 4 ,
.Xr gre 4 ,
.Xr inet 4 ,
.Xr ip 4 ,
.Xr netintro 4 ,
.Xr protocols 5 ,
.Xr ifconfig 8 ,
.Xr sysctl 8
.Sh AUTHORS
.An Andrey V. Elsukov Aq Mt ae@FreeBSD.org
